fix(rtcstats): fix typo in dashboard display name

Author: Taukon

log-analyser/grafana-provisioning/dashboards/rtcstats.json

@@ -428,7 +428,7 @@
             "properties": [
               {
                 "id": "displayName",
-                "value": "unknow"
+                "value": "unknown"
               }
             ]
           }